<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <style>
            *{
                margin: 0px;
                padding: 0px;
                list-style:none;
            }
            div{
                width: 520px;
                height: 280px;
                margin:100px auto;
                position: relative;
                overflow: hidden;
            }
            ul{
                width: 9999px;
            }
            ul li{
                float: left;
            }
            ol{
                position: absolute;
                bottom:20px;
                left: 50%;
                transform: translateX(-50%)
            }
            ol li{
                width: 8px;
                height: 8px;
                background:white;
                border-radius: 50%;
                margin:0px 4px;
                float: left;
                cursor: pointer;
            }
            span{
                position: absolute;
                background:red;
                top:50%;
                transform: translateY(-50%);
                cursor: pointer;
            }
            span:nth-of-type(1){
                left: 10px;
            }
            span:nth-of-type(2){
                right: 10px;
            }
            .current{
                background: black;
            }
        </style>
    </head>
    <body>
        <div id="w">
            <ul id="b">
                <li>
                    <img src="1.jpg" alt="">
                </li>
                <li>
                    <img src="2.jpg" alt="">
                </li>
                <li>
                    <img src="3.png" alt="">
                </li>
                <li>
                    <img src="4.jpg" alt="">
                </li>
            </ul>
            <ol id='l'> 
                <li class='current'></li>
                <li></li>
                <li></li>
                <li></li>
            </ol>
            <span id="l"><</span>
            <span id="r">></span>
        </div>
        <script>
            var box=document.getElementById('b');
            var wrap=document.getElementById('w');
            var left=document.getElementById('l');
            var right=document.getElementById('r');            
            var list=document.getElementById('l').children
            var num=0;
            var timer;
            function fn(){
            timer=setInterval(function(){
               num++;
               if(num>3){
                   num=0;
               }
               var t=-num*520;
                box.style.transform='translateX('+t+'px)';
                for(var j=0;j<list.length;j++){
                    list[j].className='';
                }
                list[num].className='current'
            },1000)
            }
            fn()
            wrap.onmouseenter=function(){
                clearInterval(timer)
            }
            wrap.onmouseleave=function(){
                fn()
            }
            for(var i=0;i<list.length;i++){
                list[i].index=i;
                list[i].onclick=function(){
                for(var j=0;j<list.length;j++){
                list[j].className='';
                }
                this.className='current';
                num=this.index;
                var t=-num*520;
                box.style.transform='translateX('+t+'px)';
                }
            }
           left.onclick=function(){
               num--;
               if(num<0){
                   num=3;
               }
               var t=-num*520;
                box.style.transform='translateX('+t+'px)';
                for(var j=0;j<list.length;j++){
                    list[j].className='';
                }
                list[num].className='current'
            }
            right.onclick=function(){
               num++;
               if(num>3){
                   num=0;
               }
               var t=-num*520;
                box.style.transform='translateX('+t+'px)';
                for(var j=0;j<list.length;j++){
                    list[j].className='';
                }
                list[num].className='current'
            }
        </script>
    </body>
</html>